Why do you need to keep urine warm?
Since initial drug screening does not typically include a special test for a sample’s validity, the testing staff just checks the temperature of the urine to make sure it hasn’t been substituted. Real human urine is warmed by the body, and it logically follows that a fresh sample should also be warm; otherwise, it must have come from somewhere else other than your body. That is why fake piss must be kept warm if you don’t want your sample to be rejected even before an actual drug test.
How warm should a sample be?
The normal temperature of human urine ranges from 94°F to 96°F (about 35°C). The temperature of a drug test sample must be measured during the first 4 minutes after it was received, as the sample changes depending on the ambient temperature. Acceptable range is from 90°F to 100°F (32°C - 38°C). Any sample with a temperature outside this range will immediately be suspicious.
Container cups for samples usually have a built-in thermometer that registers the temperature of the piss as soon as it enters the container. So while you can easily buy synthetic urine hiding it and using it to successfully pass a drug test can prove to be more difficult.
Microwaving synthetic urine
Microwaving fake piss is by far the easiest way to bring it to the desired temperature. All you need to do is place the container with the urine into a microwave and heat it for about 10 seconds. You can use a temperature strip to check if the sample is usable. Leaving the urine in for a longer period will give it an unusually high temperature, which is when the situation becomes tricky. You can wait for the sample to cool down a little, but you should know that synthetic urine can be destroyed by too much heat.
Using hand warmers
Hand warmers are small, readily available, and an easy way to heat synthetic urine. Just pour the liquid into a small container or a sealed bag, wrap the hand warmer around it, and secure by using tape or an elastic band. Take note that different hand warmers work in different ways. Some get warm as quickly as they get cold in a span of a few short hours. Warmers that maintain steady heat in the 90°F to 100°F range are perfect, but you might also want to pick one that will maintain the heat for as long as you need it.
Own body heat
Using your own body is another popular method to keep synthetic urine warm. Place the sample in a sealed plastic bag, and maintain the required temperature by placing it near a warm part of your body, which is always a matter of personal preference. Most men tend to use their crotch area—their inner thighs or inside their underwear. Some women prefer to use their armpits or inside their bras.